This invention relates to a rotor for a rotary internal combustion engine of the kind, hereinafter referred to as being of the kind specified, in which a rotary piston or rotor, rotates within a cavity in a housing, the rotor and the walls of the cavity being so shaped that working chambers are formed therebetween which vary in volume as the rotor rotates, and the cavity being provided with inlet and exhaust parts.
More particularly, but not exclusively, the invention relates to a rotor for a so-called Wankel engine in which the housing has a two-lobed epitrochoidal bore which forms the cavity and has end plates which form axially spaced end walls closing the cavity, the rotor having an outer profile of generally equilateral triangular shape with outwardly curved sides such as convexly curved sides, and the rotor being mounted on an eccentric journal of a main shaft and being geared to rotate in a planetary manner within the cavity at one third of the speed of rotation of the main shaft.
A rotor for a Wankel type engine is described and claimed in our previous patent No. GB 2,100,795, the rotor comprising a body havng an inner profile providing part peripheral location portions in the regions of the mid points of the rotor sides which are engaged by an insert, the insert having a bearing part and an indexing gear of the rotor, the inner profile of the body adjacent to each apex of the rotor providing, with the insert, axially extending cooling passages.
In the rotor described in our previous patent, the insert is secured in position by drive pins and grub screws which extend parallel to the axis of rotation of the rotor which pins and screws are located between the insert and the inner profile of the body in passageways which are defined partly by the insert and partly by the inner profile of the rotor body.
Although such a securing means has proved satisfactory for motor cycle engines, problems have been encountered in engines which are run continuously at high powers, such as engines which may be used in boats and in aeroplanes.
It has been found that during prolonged overload testing, the axial screws and axial drive pins tend to work loose thus permitting the insert to move slightly axially and/or circumferentially relative to the rotor body.
Accordingly a new means of securing the insert to the body of the rotor has had to be found.